Composite-rubber heel



Nov. 12, 1929. WILLIS 1,735,369

COMPOSITE RUBBER HEEL Filed July 5, 1928 14 v1/ z QZZflWZW 1 %1 m# VMZQPatented Nov. 12, 1929 UNITED STATES,

PATENT OFFICE GLENN H. WILLIS, OF AKRON, OHIO, ASSIGNOR TO JOHN L.SNYDER, OF AKRON, OHIO COMPOSITE-RUBBER HEEL Application filed July 5,1928. Serial in. 290,309.

This invention relates to rubber heels of the type employing a seatinglayer vulcanized to the heel body and strengthened with an intermixtureof reinforcing material.

The use of embedded metallic washers for retaining the nail heads hasheretofore been nearly universal, although inserts of wood have latelybeen used to some extent, thereby reducing the labor and material costbut giving a less flexible and resilient heel.

The object of my invention is to provide a heel of relatively-highflexibility and resiliency without the use of metallic washers and at areduced labor cost. To this end I employ an attaching plug or layerinseparably bonded by vulcanization to the heel body, said layer beingof leathery firmness, that is, sufficiently hard to retain the nailheads and counteract the spreading tendency of the softer rubber of saidheel body, but also possessing some resiliency which contributes to thecushioning properties and enough fiexibility to produce a tight seatingof the heel, especially at the edges.

I have found that these characteristics are obtained by incorporating inthe rubber compound of the attaching plug or layer a reinforcement ofgrain hulls, the preferred ma terial being oat hulls.

Of the accompanying drawings:

Fig. 1 is a top plan view of a rubber heel embodying my invention.

Fig. 2 is a perspective view of the attaching plug or layer. a

Fig. 3 is a sectional view of a portion of a heel'mold containing theheels, which are shown in transverse section.

In the drawings, 10 is the resilient heel body composed of suitablerubber compound such as a good reclaimed rubber, with or without newrubber, and containing the usual pigments, sulphurfor vulcanization andaccelerator.

The attaching layer is a shallow inlay or plug 11 composed of rubbercompound of about the same (tlallty as the body compound, or it may be ac a reinforcement consisting of grain hulls 12 distributed throughoutits mass. The best 50 hulls I have found for the purpose are oat eaperquality, together with hulls which are relatively cheap and of highreinforcing value. Since ,they replace a con- The proportion of oathulls employed is approximately thirty percent of the total weight ofthe stock in the attaching layer, but this proportion may beconsiderably varied. The rubber stock in the layer 11 is made relativelysoft or sappy by, the introduction of five to six percent of a flux orsoftener such as cottonseed oil, palm oil or a suitable combination ofvegetable and mineral oils in order to facilitate the distribution ofthe hulls throughout the plastic rubber. Milling is preferably performedon even-speed rolls having an open setting to avoid a bank and the hullsare fed between the rolls into the sheet which follows one of the rolls,the opening being increased as the volume builds up.

When a homogeneous mixture has been obtained, the compound is run into asheet of the desired thickness and flat blanks or plugs 11 of the shapeshown in Fig. 2 are died out of said sheet. For each heel, one of theseplugs is located in the cavity of a vulcanizing mold 13 to forman inlayon the attaching face of the heel and is retained in proper p osition bypins 14 on the lower mold plate.

he body plug, the mold is then closed and the heel vulcanized, both bodyrubber and plug being completely cured in the sameperiod of time.

The labor cost for making heels with these rubber being placed againstthe attaching layers is less than for the common embedded washers andthe reto spread substan around the edges is insured When the heel isnailed in place. The firmness oft-his inla-y resists the tendency of thesofter body rubber tially after the attachment has been efiected.

The drawing illustrates a preferred form and arrangement of attachinglayer reinforced as described but the details can be varied Withoutdeparting from my invention. This idea may also, if desired, be utilizedfor attaching rubber soles to shoes.

I claim:

1. A composite, vulcanized rubber shoe tread which is flexible andresilient throughout, said tread comprising a rubber cushion Wearingbody, and an attaching layer of leathery firmness integrally vulcanizedto said cushion body and formed of rubber intermixed With grain hulls,said layer being adapted to retain nail heads and resists the lateralspreading tendency of the cushion body.

2. A composite, vulcanized rubber heel comprising a rubber cushion body,and a flexible, resilient, attaching layer integrally united Wit-h andinlaid in the seating face of said body, said layer being composed ofrub ber compound containing grain hulls having substantiallythestifiness of oat hulls.

3. A composite, vulcanized rubber heel comprising a rubber cushion body,and a flexible, resilient, attaching layer integrally united With andinlaid in the seatin face of said body, said layer being composed ofrubber compound containing a minor proportion of oat hulls.

In Witness whereof I have hereunto set my hand this 29th day of June,1928. I GLENN H, LIS.

